after attached hdd thru usb missing some corel wordperfect .irs files, system win98 fat, possible carving or repair, what best
tools and procedures, and where to find signatures for that files
thanks

Due to its inherent limitations, file carving is the last choice, not the first choice. Therefore I would not start with that approach.

Instead, IMHO get a better diagnosis of the real problem first i.e. just attaching a disk via USB should not corrupt files, so what exactly has happened in your case? Better recovery and/or understanding of the filesystem state, can prevent the need to use file carving.

However if you are angry that I have not answered your specific question, then just ignore this reply

P.S. I see that you have asked the same question on at least one other forum e.g.:

http://www.forensicfocus.com/Forums/vie ... p=6558385/

so I suggest that any readers here may want to check that thread, to prevent wasting their time duplicating any replies which might appear there.